class Command:
    def execute(self):
        pass

class Receiver:
    def action(self):
        print("Action performed")

class ConcreteCommand(Command):
    def __init__(self, receiver):
        self.receiver = receiver

    def execute(self):
        self.receiver.action()

class Client:
    def __init__(self):
        self.receiver = Receiver()
        self.command = ConcreteCommand(self.receiver)

    def invoke(self):
        self.command.execute()

# Usage
client = Client()
client.invoke()

'''
代码实现：
Action performed
'''